Drilling-machine.



H. T. DUNBARY.

DRILLING MACHINE.

APP 1913- 1 203,860. Patented Nov. 7, 1916.

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DRILUNG MACHINE.

APPLICATION FILED III/III. 20. 1913.

Patented. Nov. 7, 1916.

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H. T. DUNBAR.

DRILLING MACHINE.

APPLICATION FILED MAR. 2o. 1913 1,203,860. Patented Nov. 7, 1916.

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mm uuml INVENTDR vAT1-.C1RNEYEJ HARRIS T. DUNBAR, 0F BUFFALO, NEW YORK.

DRILLING-MACHINE.

i Specification of Letters latent.

Patented Nov. 1916.

Application filed March 20, 1913. Serial No. 755,577.

To all whom t may concern:

Be it known that I, HARRIS T. DUNBAR, a citizen of the United States, residing at Buffalo, in the county of Erie and State of New York, have invented new and useful Improvements in Drilling-lliachines, of which the following is a specication.

This invention relates to a drilling machine for forming holes in rocks and the like. A. machine for this purpose is shown in an application for patent liled by myself May 2%, 1912, Serial #699,394, patented March 21, 1916, No. 1,176,041.

The objects of the present invention are to provide improved means for movably.

supporting the guide tube which carries the reamer drill or bit and which receives the drill rod whereby the bit is operated; to provide improved means for rotating the guide tube; to provide a valve mechanism whereby at the end of the drilling movement the water pressure will be shut off from the motor which rotates the bit and directs the water into the guide tube for washing out the drill hole while the bit is at rest, and to stop the operation of the drill rod when the drill hole has reached a certain depth; and to provide means whereby the weight of the counterbalancing device 'will be temporarily removed from the guide tube, the drill rod motor and the bit rotating motor and associated parts while the drill rod is delivering a blow against the bit and thereby prevent interfering with the efficiency of the drilling apparatus.

In the accompanying drawings: Figure 1 is a front elevation showing an embodiment of my invention for drilling holes in rock on land. Fig. 2 is a side elevation thereof, partly in section. Fig. 3 is a fragmentary vertical longitudinal section, on an enlarged scale, of the upper part of the drilling ma chine. Fig. 4 is a horizontal section taken in line 4 4, Fig. 3. Fig. 5. is a fragmentary vertical longitudinalfsection, on an enlarged scale, of the lower part of the drilling machine. Fig. 6 is a vertical transverse section, on an enlarged scale, showing the valve for controllinglthe supply of air pressure to the air motorY which reciprocates the drill or rod.

Fig. 3. Fig. 7 is a similar view of the said section being taken in line 6 6,

whereby the water pressure to the bit rotating motor and to the guide tube is controlled. Fig. 8 is a sectional view of a portion of the mechanism for controlling the last mentioned valve. Figs. 9, 10 and 11 are horizontal sections in lines 9 9, 10 and 11, Fig. 5, respectively. Fig. 12 is a fragmentary vertical longitudinal section of the drilling machine showing the counterbalancing weight and associated parts whereby the weight of the motors, the bit, drill rod, guide tube, and associated parts are counterbalanced. Fig. 13 is a rear elevation of the counterbalancing weight and associated parts. Fig. k111 is a horizontal section, taken in line 14-14, Fig. 13.

Similar characters of reference indicate corresponding parts throughout the several views.

The working parts of this drilling mai chine are preferably mounted upon a derrick which may be moved about from place to place wherever the drilling is required which derrick may be variously constructed, that shown in the drawings as an example being suitable and comprising a lower triangular base 1, two upright front guide bars, rails or tracks 2, 2 rising from the front part of the base, and a single inclined rail, bar or track 3 arranged in rear of the front guide bars and connected at its upper front end with the upper ends of the front guide Vbars and at its lower end with the rear part of the base. This derrick may be moved about from place to place in the manner of a cart by means of wheels 4, 4 arranged on opposite sides of the base and after the derrick has been shifted to the desired position the same may be retained in place by lifting the same so that it does not rest on its wheels, this lifting being preferably effected by means of a plurality of vertical screws 5, working in threaded blocks 6 arranged on opposite sides and at the rear of the base and each screw provided with a pointed lower end adapted to engage the ground or surface of the rock and provided at its upper end with a handle 7 for turning the same. By means of these screws the derrick may be lifted so that the weight rests onthese screws and the wheels are rendered inoperative, thereby preventing displacement of the derrick while the drill ing apparatus is in use.

S represents a vertically movable drill carriage or slide which supports the various parts of the drilling apparatus proper such as the bit, the hammer rod for driving the bit, the guide tube which supports the bit and guides the hammer rod, the air motor for reciprocating the hammer rod and the water motor for rotating the guide tube and bit. This carriage moves vertically between the front guide bars and is guided thereon by means of a cross head 9 secured to the carriage and having its opposite ends constructed to form guide jaws 10 which receive the opposing inner edges of the front guide bars, as shown in Figs. 1 and 4. lThe body of this carriage is made hollow so that the same forms a transfer chamber 11 for a purpose to be hereinafter described.

Although the reamer bit or drill whereby the drilling or boring of the rock is effected may be variously constructed that shown in the drawings comprises a narrow contracted upright drill rod or hammer bar 15, a plulality of cutting blades or cutters 13 arranged at the lower end of the drill rod and projecting laterally7 therefrom and each having a sharp or pointed lower end or edge.

The drill rod is preferablyV of cylindrical Yform in cross section and projects at its Lipper' end into the transfer chamber 11 from the lower end thereof and is operatively connected with a motor whereby the drill rod is reciprocated vertically. This motor may be of any suitable construction and operated by any suitable power medium but it is preferable to use for this purpose an air operated motor. ln its preferred form this air motor comprises a working cylinder 1G arranged vertically above the transfer chamber 11. a piston 17 arranged within the cylinder, a piston rod 1S extending downwardly from the piston through a stuffing box 19 on. the lower head of the air cylinder', and a coupling 20 connecting the lower end of the piston rod and the upper end of the drill rod within the transfer chamber. At its lower end the cylinder of the air motor is provided with a laterally project-ing annular lange 2l which is secured to the upper end of the transfer chamber 11 so that this flange and the lower head of the' air cylinder form a head or closure for the upper end of the transfer chamber. Compressed air is supplied to the cylinder`of the air motor by means of a pipe i2 connected with the upper end of the cylinder, and the distribution of the air for causing the same to alternately raise and lower the air piston is effected bv a valve mechanism which may be of a suitable and well known construction but as the same forms no part of this invention the same is not herein shown and described. The passage of compressed air from the pipe 22 to the air motor is controlled by a valve which preferably comprises a casing 23 connected with said pipe and provided with a port 24, a gate or valve disk 25 movable transversely within the casing s0l as to either uncover the port 24, as shown in Fig. 6, or to extend over this port for the purpose of closing the same and shutting off the passage of air through the supply pipe to the air motor, a roel: shaft 26 journaled in a bearing on one side of the valve casing and provided within the casing with an internal rock arm Q? whereby the gate or valve disk is shifted laterally toward and from the port, and an external rock arm 28 secured to the outer end of the rock shaft 26 and forming means whereby the valve may be opened and closed.

While the drill rod is raised and lowered continuously by the air motor the bit at the lower end thereof is driven with a blow at the lower end :of each downward stroke against the rockto be bored and at the same time the bit, rod and piston are slowly turned, the drill rod and bit are supported in an upright position and guided in their vertical movements and a stream of water is conducted into the drilled hole of the rock so as to wash out the particles of rock which have been cut away. The means for accomplishing the purposes just mentioned comprise an upright guide tube which in the preferred form shown in the drawings consists of upper, intermediate and lower' tubular body sections 29, 30, 31 and tubular coupling sections 32 connecting the body sections. rlhis tube incloses the drill rod and the drill bit for the purpose of guiding and holding these parts in their proper working position. The uppermost body section 29 of the guide tube is arranged within a stufling box 233 on a head or cap 3fthaving an upper enlargement secured to the lower end of the transfer' chamber 11. so that said uppermost body section opens at its upper end into this chamber. "u At its upper end the uppermost body section 29 of the guide tube is provided with an upwardly Haring external flange 35 which is provided on its upper side with a bearing ring 36 engaging' with an annular Vbearing groove 37 in the lower end of the transfer chamber7 as shown in Fig. 3, thereby forming a rotatable joint between this chamber and the upper end of the guide tube, whereby a water tight joint is formed between these parts and the weight of the drill carriage and connecting parts is caused to bear downwardl against the Ouide tube. The Ouide b D 23 tube is prevented from dropping away from the transfer chamber by means of an annular downwardly facing shoulder 38 formed on the exterior of the uppermost body section below the flaring flange thereof and engaging with an upwardly facing shoulder 39 formed on the interior of the cap 34 between the stuffing box and the upper enlarged part thereof. as shown in Fig. 3. The opposing ends of the body sections of the guide tube llt are connectedr by one of the coupling sections 32 each of which has a central enlarged cylindrical part l0, two reduced cylindrical parts 4l at its oppositeY ends thereof, and two conical externally screw threadedintermediate parts l2 between the enlarged central aart andY the reduced' end parts. Each of the coupling sleeve sections is screwed with its opposite conica-l threaded parts into the conical internally th-readed ends of two opposing body sections so that the latter abut against opposite sides of the enlarged central part of this sleeve and the reduced conical ends of this sleeve engage with the unthreaded bores of the respective body sections, as shown in Fig. 5. The di- :mieter of the enlarged central part of each coupling sleeve is the saine as the external diameter of the body sections of the guide tube so that these parts when assembled are flush on the outer sidesthereof. At its lower end this guide tube passes through a cylindrical guideway formed in a guide bracket Ji-3 mounted on the lower part of the derrick, as shown in Figs. l, 2 and 5.

The number of body and coupling sections forini'ng the guide tube may be varied according to the depth at which the rock is tol be bored or the distance which the same may be below the water. By means of the coup-ling sleeves the drill rod which passes through these sleeves is supported at intervals within the guide tube which permits the drill rod to be made comparatively long and of small diameter without liability7 of this rod buckling or bending as it is driven downwardly against the cutting bit, thereby avoiding making the drill rod unduly heavy. The dia-meter of the bere of each of the coupling sections is however, greater than the diameter of the periphery of the drill rod so as to form an annular channel or passageway between these parts through which the water may liow from the transfer chamber 1l downwardly through the guide tube.

The cutting blades of the drill rod 13 project laterally through longitudinal slots ll formed in the lowermost body section and extending upwardly from the lowery end thereof so that the drill rod and bit are compelled to turn with the guide tube but the drill rod and bit are free to rise and fall independently of the guide tube. The diameter of the several blades of the cutting bit is somewhat greater than the eX- ternal diameter of the guide tube so that the latter can move downwardly freely into the hole cut in the rock by the bit. The diameter of the rod of the cutting bit is smaller than that of the bore of the lowermost coupling section 32 which receives this rod so as to form an annular water passage between this rod and this coupling section surface ofV theV through which the water can pass downwardly to the lower end of the guide tube.

During the operation of drilling or boring a hole in the rock the lower end of the guide tube rests upon the rock. Upon starting the air engine or motor while the parts are in this position the drill rod or bar will be raised and lowered continuously and during each downward stroke of the rod the bit strikes the rock, whereby the lower cutting or chisel edges of the blades of the bit are driven into the surface of the rock, thereby cutting away a portion of the rock. lVhile the cutting bit or chisel is thus reciprocate-d, the same is turned slowly so as to bring its cutting edges into engagement with new parts. of the roch during each downward stroke thereof7 and thereby cause the rock to be gradually cut away in comparatively small bits, chips or powder. The pulverized rock thus produced in the hole by the bit is removed therefrom by the stream of water which passes from the lower end of the transfer chamber 1l dcwn-` wardly through the guide tube and past the drill rod and bit and thence upwardly through the space between theguide tube and the bore of the hole in the rock7 whereby the cutaway particles of rock are carried upwardly out of the hole and to the upper` surface of the rock.

Various means may be employed for turning the guide tube and the bit and drill rod connected therewith but those shown in the drawings are suitable and preferred and are constructed as follows: 45 represents the casing or body of a motor which is adapted to be driven by water supplied thereto under pressure and which is operatively connected with the guide tube for producing a rotary motion of the latter. The casing of this water motor is mounted on the lower part of the drill carriage so as to rise and fall with the guide tube and the air motor which reciprocates the drill rod. Arranged centrally in the casing of the water motor is an upright crank shaft which is ournaled with its upper and lower ends 6,47 in bearings formed inthe upper andlower parts of the water motor casing. Between the upper and lower ends of the crank shaft the same is provi( ed with a, valve disk 5l of substantially circular form. rlhe valve disk of the crank shaft rotates within a cylindrical valve chamber formed in the central part of the casing or ho( y of the water motor with its upper and lower sides engaging with the top and bottoni of this valve chamber. Vllater under pressure is supplied to this valve chamber through a branch pipe GO forming one of the branches of a main water supply pipe 61 which latter receives water under pressure from any Suitable source. The upper end of the crank communicates by means of a Vse from this motor to the guide tube.

passage er conduit Geli with the lower end of the transfer chamber. As the water enters the valve chamber under pressure the same produces a continuous rotary motion of the crank shaft.

Motion is transmitted from the crank shaft tothe guide tube of the drill rod and bit by means of a pinion 77 formed on the upper end of the crank shaft and meshing with a gear wheel or rim 7S arranged on the outer edge or margin of the annular flange on the uppermost section of the guide tube., as shown in Fig. 3.

When the drilling operation is arrested it is necessary to continue the supply of water to the guide tube in order to keep on washing out the hole which has been drilled in the rock notwithstanding that the operation of driving the bit against the rech and also rotating the same has been arrested. Means are therefore provided for supplying the guide tube with water under pressure when the water operated bit rotating motor has been arrested and no water is discharged 1n its preferred organization. this water controlling means is operated in combination with the means which supply air to the air operated motor of the drill rod, so that while the bit is drilling a hole into the roclr of a predetermined length or depth the controlling valve in the air supply pipe of the drill rod motor will remain open and water under pressure will be supplied to the bit rotating motor and no water will be supplied directly to the guide tube, but when the drill or bit has reached the limit of the depth of hole which it was intended to bore the rock the water supply will be cut off from the bit rotating motor and be passed directly into the guide tube and at the same time the valve in the air supply pipe will be shut so as to arrest the operation of the drill rod motor. This stoppage of the water motor and the air motor and the diversion ofthe water supI pl directly to the guide tube is preferably effected automatically when predetermined depth of hole has been bored into the roel; by means which are preferably constructed as follows: 79 represents another branch )i 3e leading from the water sup Jlv pipe 6l l l s i i i to the transfer chamber and 80 represents the casing of a three-way valve which is interposed between the main water supply pipe and the branches 61. and 79, so that upon turning the rotatable plug 81 of this valve into one position the water from the main pipe will be directed to the water motor but cut olf from the transfer chamber, as shown in Fig. 7, while upon turning this plug a quarter turn in the direction of the arrow, in Fiom 7 the water supply of the main pipe will be shut off from the branch pipe 61 leading to the water motor but permitted to pass through the branch pipe 7 9 to the transfer chamber. 1n this way water is supplied to the guide tube either indirectly through the water motor or directly through the transfer chamber so that water is always delivered into the drill hole for washing out the chips or pulverized rock therefrom. At its outer end the valve plug of the threeway valve is provided with a lever one arm 82 of which is connected by means of a connecting rod 83 with the outer arm 2S of the air valve shaft while the other arm 8% of said lever is attached to a shipper rod 85 extending downwardly therefrom to within convenient reach of the operator. Means is provided which tends constantly to close the air valve and to move the plugrof the three-way water valve into a positionin which the water supply is eutV off from the water motor and connected directly with the guide tube, which means preferably consists of a spring S6 connected at one end with the outer arm 28V of the air valve while its opposite end is connected with an adjacent stationary part of the drill carriage. Upon pulling downwardly on the shipper rod 85 the rock lever of the three-way water valve and the outer rock arm of the air valve are simultaneously turned in a direction for opening the air valve and turning the plug of the three-way water valve into the position in which a direct connection between the main water supply and the guide tub-e is cut off but water is admitted to the water motor, as shown in full lines in Figs. 6 and 7. Upon moving the gate of the air valve and the plug of the three-way water valve into the position just described,'the spring 86 is strained and therefore tends constantly to shift said gate and plug in the opposite direction but this is prevented by means of a dog 87 pivoted on the drill carriage adjacent to the three-way water valve and engaging with a shoulder 88 on the hub of the lever 82, S4 of this valve, as shown in Fig. 8. This dog drops into engagement with this shoulder automatically by gravity when the three way plug of the water valve and the gate of the air valve have vbeen shifted into the position for opening the air valve and supplying water to the water motor. represents a tappet arranged on the lower part of the derrick in line with a heel on the dog 87. As shown in the drawings, the three-way valve is arranged adjacent to the right side of the drill carriage and the tappet 89 is mounted on the lower part of the right hand front guide bar and is capable of vertical adjustment on this guide bar so that the same maybe engaged earlier or later by the heel of the dog in accordance with the depth of hole it is desired te drill into the rock. As the drilling or eut ting bit reaches the depth of bore in the rack fer which the tappet has been set the heel of the dog 87 engages with this tappet so that this dog is disengaged from the shoulder of the lever ot the three-way water valve, and when this occurs the spring 86 instantly turns the three-way valve lever and air valve rock arm 2S so as to shut oft the supply of compressed air to the drill rod motor and the supply of water to the bit rotating motor and cause water to be admitted directly to the guidetube for continuing washing out of the hole which has been bored in the rock. By this means the bit and its guide tube are always free to lbe removed from the hole which has been drilled and the latter is thoroughly washed out so as to permit a blasting charge to lbe always readily placed in the lowermost part otl the hole which has been drilled in the rock. l Y

ln order to counterbalance the weight ot the drill carriage and the parts 1mounted thereon so as to avoid pressing thel lower end ot' the guide tube unduly against the bottom of the hole which is being bored in the rock and also to permit ot more easily raising the working parts of the drilling apparatus, a counter-balancing device is provided which is preferably constructed as follows: 91, 91 represent the two sections ot a main counter-balancing weight which are connected by means of a plurality of trans verse bolts 92 and whichhave the front por tions of their opposing sides provided with guide grooves 93 which receive the opposite edges of the rear flanged edge oi' the rear guide bar of the derrich so vthat this main counter-balancing weight may be moved up and down on thisguide bar. A connection between this main counter-balancing weight and the drill carriage is produced by means or' a cable 94C passing with its intermediate part around a sheave 95 mounted on the upper end of the derricl, said cable being connected with its depending front end toa bail 90 secured to the upper end of the drill carriage while its depending rear end -is connected by means of la link 97 with the uppermost coupling bolt ot the main counter-balancing weight. For the purpose of enabling the eiifectiveness of this counterbalancing weight to be adjusted with approximate nicety to suit the weight of the drill carriage and the parts mounted thereon one or more supplemental counter-balancing weights may be provided each of which is composed of two sections 98Iwhich are adapted to be mounted on top ofthe main counter-balancing weight and connected with each other by means of a transverse bolt 99 so that the front parts of these supplemental weight sections may be slidingly engaged with the rear guide bar of the derrick by means of guide4 grooves in substantially the same manner as the main weight sections.

It the counter-balancing weight were perdrilling bit against the rock would tend tol also lift theair cylinder and the parts connected therewith and the t'ull effect of the air pressure on the bit would not be obtained; Means are therefore provided for temporarily removing the eect of the counter-balancing weights the instant the air pressure in the upper end of ythe air cylinder etects the initial portion of the lifting movement of this cylinder and the parts connected therewith, so that the counter-balancing weight at this time is liminated andthe full weight of the drill carriage and the parts connected therewith operates to resist rising' of the drill Car- 'iage, air cylinder and associated parts so that the compressed air iscompelled to eX pend its .tull force in moving the air piston downwardly and delivering a blow of maximum Jforce of the bit against the bottom of the drill hole. The means for thus temporarily removing the effect ot the counter-balancing weight from the drilling apparatus is so designed that it automatically follows up the bit inthe vsame measure as the same descends during the increase in depth of the drill hole. The preferred means for accomplishing the purpose just described comprises a plurality of detent pawls 200 which are arranged in a vertical row between the opposing inner sides ot the main counter-balancing weight sections, each of these pawls being pivoted vertically on one ot the coupling bolts 99 and having its inner arm 100 constructed in the form ot' a jaw which is adapted to engage one or another oi' an upright row of detent or ratchet teeth 101 arranged in the form of a rack on the rear edge ot the rear guide bar of the dei-rick .while the rear arm 102 ofthis pawl is provided with a weight 103 :tor turning the saine in a direction which will keep its jaw or front arm in engagement with said detent teeth. rlhe several detent pawls are A;

so spaced relatively to the detent teeth on the derrick that only one of these detent pawls at a timewill engage with these teeth and the several pawls will engage with a detent tooth at la different time. By this means a comparatiyely-coarse spacing of the detent pawls is possible and still a comparatively fine detent eect is obtained which will arrest the downward movement ot' the counter-balancing weight the instant the drill carriage and associated parts tend to rise luider the pressure of the air in the air cylinder and release the upward pull on the counter-balancing weight. It will thus be seen that by means of this detent device the counter-balancing weight is free to rise on the rear guide bar of the derriolr as the drilling apparatus with which it is connected descends on the front guide bars and therefore operate to counter-balance the weight of the latter, but when the air pressure in the air cylinder tends to lift this cylinder and the parts operatively connected therewith the counter-balancing weight becomes interloclred with the derrick so that the same is temporarily ineffective and enables the maximum efliciency of the air pressure to be utilized for drilling purposes. Whenever it is desired to again lower the counter-balancing weight all of the detent pawls are shifted out of engagement with the detent or ratchet teeth when the counterweight can be freely lowered.

The preferred means for disengaging the detent pawls from the detent teeth are so organized that these pawls may be simultaneously shifted into their inoperative position which means comprise a vertical yoke or bar 104 embracing the rear arms of the several detent pawls and provided with a plurality of transverse shoulders or pins 105 each of which is arranged below the rear arm of one of the detent pawls, a shifting lever 106 pivoted on the main counterbalancing weight between the upper rear parts of its sections and connected with its front arm to the upper end of the yoke, and a shifting line or rod 107 running from the rear arm of the shifting lever downwardly to a point within convenient reach of the operator. As the operator pulls downwardly on the rod or line 107 all of the detent pawls are disengaged from the detent rack, thereby permitting the counter-balancing weight to be pulled downwardly on the rear guide bar and the drilling apparatus to be elevated on the front guide bars of the derrick.

1 claim as my invention:

1. A drilling machine comprising a chamber adapted to receive and deliver a pressure medium and having an open lower end, a guide tube communicating at its upper end with the lower end of said chamber so as to receive the pressure medium therefrom and bearing at its upper end against the lower end of said chamber, a drill rod reciprocating in said tube and provided at its lower end with a bit which is compelled to turn, with said tube but free to move lengthwise independently thereof, and means for rotating said tube.

2. A drilling machine comprising a chamber adapted to receive and deliver a pressure medium and having an open lowerI end, a guide tube communicating at its upper end with the lower end of said chamber so as to receive the pressure medium therefrom and provided at its upper end with an upwardly flaring flange which bears against ysure medium and having an open lower end,

a guide tube communicating at its upper end with the lower end of said chamber so as to receive the pressure medium therefrom and provided at its upper end with an upwardly flaring flange which bears against the lower end of said chamber, a drill rod reciprocating in said tube and provided at its lower end with a bit which is compelled to turn with said tube but is free to move lengthwise independently thereof, and means for rotating said tube comprising a gear rim arranged on said flange and a motor having a pinion meshing with said gear rim.

4. A drilling machine comprising a chamber adapted to receive and deliver' a pressure medium and having an open lower end, a guide tube communicating at its upper end with the lower end of said chamber so as to receive the pressure medium therefrom and bearing at its upper end against the lower end of said chamber, a cap inclosing the upper end of said tube and secured at its margin to the lower end of said chamber and provided centrally with a stuliing boi; in which said tube turns and a drill rod which reciprocates in said tube.

5. A drilling machine comprising a rotatable guide tube, a bit mounted on said tube so as to turn therewith but be capable of lengthwise movement independently thereof, a drill rod reciprocating in said guide tube and operatively related to said bit, a water motor operatively connected with said tube for turning the same and having its water outlet communicating with the upper end of said guide tube, a water supply pipe having a branch communicating with the inlet of said motor and another branch communicating with the upper end of said guide tube, and a water controlling valve for directing the water from said supply pipe into either one or the other of said branch pipes.

6. A drilling machine comprising a rotatable guide tube, a bit mounted on said tube so as to turn therewith but be capable of lengthwise movement independently thereof, a drill rod reciprocating in said guide tube and operatively related to said bit, a water motor operatively connected with said tube for turning the same and having its water outlet communicating withV the upper end of said guide tube, a water supply pipe having a branch communicating with the inlet of said motor and another branch communicating with the upper end of said guide tube, a water controlling valve for directinO the water trom said sua l .D pipe into either one or the other ot sait branch 31 )es a derrick on which said motor 7 1 tubes and valve move verticali and means for automatically shifting' said valve at 'the end of the downward movement ci' said motor, tubes and valve.

f. A drilling machine comprising a derrlck, a main supporting` carriage movable vertically on said derriclr, a guide tube mounted to turn on said carriage, a bit turning with said guide tube but slidable independently thereof, a drill rod reciprocating' lengthwise in'said guide tube and operatively related to said bit, a water motel' mounted on said carriage and operatively connected with said guide tube for turning the same and having' its outlet communicating' with said guide tube, a water supply pipe having a branch leading to the inlet of said motor and another branch communicating directly with said guide tube, a valve having' a movable plug' for directing the water from said supply either to said motor branch pipe or to said guide tube branch pipe, a dog' mounted on said carriage and adapted to engage with a shoulder on said valve plug' for holding' the latter in a position in which the water supply pipe is connected with the motor and cut oil from direct connection with said guide tube, a tappet arranged on the de-rrick and adapted to disengage said dogfrom said valve plug' at the end of the downward movement ot the carriage, and a spring for turning the valve plugwhen released by said dog' so as to connect the water supply pipe directly with said guide tube and disconnect the same` from said motor.

8. drilling machine comprising' a rotatable guide tube, a bit mounted on said tube so as to turn therewith but be capable oli lengthwise movement independently thereof, a drill rod reciprocating in said guide tube and operatively rela-ted to said bit, a

1 water motor operatively connected with said tube for turning-the same `and having its water outlet communicating with the upper end of said guide tube, a water supply pipe having a branch communicatingl with the inlet of said motor and another branch communicating' with the upper end ot said .guide tube, a water controlling valve for directing' the water from said supply pipe 4into either one or the other of said branch pipes, an air operated motor for reciprocating said chamber rod and hai/'ing' an air inlet valve, and a connection between said air inlet valve and said water controlling' valve whereby upon shifting the water valve so as to deliver water to the motor the air valve will be opened and cause the air motor to reciprocate the hammer rod while upon shitting' the water valve so as to cut the water cit from the water motor and direct the same into the guide tube the air valve will be closed and the motion of the hammer rod will be arrested.

9. A drilling machine .comprising a derrick, a main supportingcarriage movable vertically on said derricl, a guide tube mounted to turn on said carriage', a bit turning' with. said guide tube but slidable independently thereof, a drill rod reciprocating' lengthwise in said guide tube and operatively related to said bit, a water motor mounted on said carriage and operatively connected with said guide tube for turning' the saine and having' its outlet communicating' with said guide tube, a water supply pipe having' a branch leading to the inlet ot said motor and another branch communieating' directly with said guide tube, a valve having' a movable plug' for directing the water from said supply either to said motor branch pipe or to said guide tube branch pipe, a dog' mounted on said carriage and adapted to engage with a shoulder on said valve plug' for holding' the latter in a position in which the water supply pipe is connected wth the motor and cut oil from direct connection with said guide tube, a tappet arranged on the derriclr and adapted to disengag'e said dog' from said valve plug' at the end of the downward movement of the carriage, a spring for turning the valve plug when released by said dog so as to connect the water supply pipe directly with said guide tube and disconnect the same from said motor, an air operated motor mounted on said carriage and having a cylinder, a piston in said cylinder and connected with said hammer rod, an air valve for controlling' the supply of compressed air to said air motor, and a connection between the closure or said air valve and the plug' of said water cont-rolling valve for causing' the air valve to be closed when the plug' of the water valve connects the water supply directly with said guide tube and disconnects the same from said water motor.

l0. ri. drilling' machine comprising' a derriclr, a. drilling' carriage movable vertically on said derricl, a drilling bit mounted on said carriage, a vertically reciprocating' drill rod for operating' said bit, a motor for operating said drill rod comprising' a piston connected with said drill rod and a cylinder mounted on said carriage and receiving said piston and adapted to be supplied with a pressure medium between its top and the upper end of said piston, and means for counter-balancing said drill carriage and the parts connected therewith comprising a counter weight slidable vertically on the derrick and operatively connected with said drill carriage, and a detent device whereby said counter-balancing weight is permitted to ascend but prevented from descending.

11. A drilling machine comprising a derriclr, a drilling carriagel movable vertically on said derrick, a drilling bit mounted on said carriage, a vertically reciprocating drill rod for operating said bit, a motor for operating said drill rod comprising a piston connected with said drill rod and a cylinder mounted on said carriage and receiving said piston and adapted to be supplied with a pressure medium between its top and the upper end of said piston, and means for counter-balancing said drill carriage and the parts connected therewith comprising a counter weight slidable vertically on the derrick and operatively connected with said drill carriage, and a detent device whereby said counter-balancing weight is permitted to ascend but prevented from descending, said detent device comprising a vertical toothed rack arranged on said derriclr, and a detent pawl mounted on said counterbalancing weight and engaging with the teeth of said rack.

12. A drilling` machine comprising a derrick, a drilling carriage movable vertically on said derrick, a drilling bit mounted on said carriage, a vertically reciprocating drill rod :for operating said bit, a motor for opera-ting said drill rod comprising a piston connected with said drill rod and a cylinder mounted on said carriage and receiving said piston and adaptedV to be supplied with a pressure medium between its top and the upper end of said piston, and means for counter-balancing said drill carriage and the parts connected therewith comprising a counter weight slidable vertically on the derrick and operatively connected with said drill carriage, and a detent device whereby said counter-balancing weight is permitted to ascend but prevented from descending, said detent device comprising a vertical toothed rack arranged on said derrick, a detent pawl mounted on said counter-balancing weight and engaging with the teeth of said rack, a releasing yoke engaging with said detent pawl, and a releasing lever pivoted on said counter-balancing weight and connected with said yoke.

13. A drilling machine comprising a derrick, a drilling carriage movable vertically on said derrick, a drilling bit mounted on said carriage, a vertically reciprocating drill rod for operating said bit, a motor for operating said drill rod comprising a piston connected with said drill rod and a cylinder mounted on said carriage and receiving said piston and adapted to be supplied with a pressure medium between its top and the upper end ot' said piston,` and means for counter-balancing said drill carriage and the parts connected therewith comprising a counter weight slidable vertically on the derrick and operatively connected with said drill carriage, and a detent device whereby said counter-balancing weight is permitted to ascend but prevented from descending, said detent device comprising a vertical row of detent teeth arranged on the derrick, and a plurality of pawls mounted in a vertical rod on said counter-balancing weight and spaced diliierent distances apart so that each detent pawl engages with one of said detentteeth at a dierent time from the other detent pawls.

lll. A drilling machine comprising a derrick, a drilling carriage movable vertically on said derrick, a drilling bit mounted on said carriage, a vertically reciprocating drill rod for operating said bit, a motor for operating said drill rod comprising aI piston connected with said drill rod and a cylinder mounted on said carriageand receiving said piston and adapted to be supplied with a pressure medium between its top and the upper end of said piston, and means for counter-balancing said drill carriage and the parts connected therewith comprising a counter weight slidable vertically on the derrick and operatively connected with said drill carriage, and a detent device whereby said counter-balancing weight is permitted to ascend but prevented from descending, said counter-balancing weight comprising two sections which are provided on their opposing sides with grooves which lreceive an upright guide flange of the dei-rick between them.

15. A drilling machine comprising a derrick, a drilling carriage movable vertically on said derrick, a drilling bit mounted on said carriage, a vertically reciprocating drill rod for operating said bit, a motor for operating said drill rod comprising a piston connected with said drill rod and a cylinder mounted on said carriage and receiving said piston and adapted to be supplied with a pressure medium between its top and the upper end of said piston, and means for counter-balancing said drill carriage and the parts connected therewith comprising a counter weight slidable vertically on the derrick and operatively connected with said drill carriage, and a detent device whereby said counter-balancing weight is permitted to ascend but prevented from descending, said counter-balancing weight comprising two sections which are provided on their opposing sides with grooves which receive an upright guide flange of the derrick between them and said detent device comprising a vertical row 'of teeth arranged on said der rick and a detent pawl arranged on said counter' weight between the sections thereof and engaging with said teeth.

iodo

Y tatable guide tube, a drill rod arranged in said tube and provided at its lower end with a bit, said bit and rod being compelled to turn with said tube but free to move axially independently thereof, means connectedV with said rod for reciprocating the same and said bit and a means for rotating said tube, rod and bit.

18. A drilling machine Y comprising a guide tube adapted to rest on the surface to be drilled and provided with guide slots in its lower end, a drill rod reciprocating lengthwise in said tube and provided at its lower end with a bit consisting of blades or cutters projecting laterally from said rod through the slots in the tube, means for rotating said tube, rod and bit, and means for reciprocating said rod and bit independently of said tube.

19. A drilling machine comprising a guide tube provided with longitudinal guide slots extending upwardly from its lower end, a bit arranged within said tube and having blades which project laterally through said slots and are shorter than the length of said slots and means connected with said bit for reciprocating the same independently ol said tube.

20. A drilling machine comprising a rotatable guide tube adapted to rest on the surface into which a hole is to be drilled, a bit arranged in -said tube and rotatable therewith but vcapable of axial movement independent of said tube, means for rotating said tube and bit, and means for delivering blows against lsaid bit.

Witness my hand this 18th day of March,

HARRIS T. DUNBAR. lllitnesses THEO. L. Porr, E. M. GRAHAM.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of `Patents, Washington, D. C. 

